Page 400 - Towards Trustworthy Elections New Directions in Electronic Voting by Ed Gerck (auth.), David Chaum, Markus Jakobsson, Ronald L. Rivest, Peter Y. A. Ryan, Josh Benaloh, Miroslaw Kutylowski, Ben Adida ( (z-lib.org (1)

A. Essex, J. Clark, and C. Adams
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Generating Commitment Lists. A “commitment list” is defined as a list of
b rows pre-printed with a monotonically increasing set of b “commitment refer-
ence numbers.” Next to each commitment reference number is a region, initially
blank, that will contain an associated value. We define two types of commitment
lists:
– Receipt commitment lists contain a set of b distinct commitment refer-
ence numbers, each with a (randomly) associated serial number
– Ballot commitment lists contain the same set of b distinct commitment
reference numbers, each with a (randomly) associated candidate list ordering.
To generate the commitment lists, we begin by considering a particular audit trail
color (e.g., pink). The pink receipt commitment list and pink ballot commitment
list are generated as follows:
1. A ballot assembly is drawn from the stack and the serial number s is noted.
A non-replaced random number i ∈ b is selected (e.g., on a slip of paper
drawn from a hat),
2. The pink audit sheet of the ballot is exposed, and the number i is written
in the commitment reference number space,
3. On the pink receipt commitment list,the number s is writteninthe blank
space beside commitment reference number i,
4. On the pink ballot commitment list, the candidate order o is written in the
blank space beside commitment reference number i.
These steps are performed on all ballot assemblies. The pink audit trail is now
complete and the goldenrod receipt commitment list and goldenrod ballot com-
mitment list (and any additional audit trail colors) can be generated in the same
manner. An example ballot assembly and corresponding entries in the commit-
ment lists is depicted in Figure 3.

Committing. For an election with two audit trails (pink and goldenrod), the
election trustees generate the pink receipt, pink ballot, goldenrod receipt and
goldenrod ballot commitment lists. They lock these values in time (i.e., commit
to them) through the following procedure:

1. Each commitment list is placed in its own appropriately labeled tamper-
evident document envelope and sealed,
2. The trustees present the sealed envelopes to the verifiers who are given the
opportunity to inspect the exterior of the envelope and sign on the flaps,
3. The envelopes are returned into the custody of the trustees.

3.3 Print Audit Selections
In order to ensure the commitment reference numbers of the ballot assemblies
point to the same candidate orderings/serial numbers appearing on the ballot
and receipt layers, some ballot assemblies will be selected by the verifiers for a
“print audit.” Procedure could vary between jurisdictions, but one recommen-
dation would be for the print audit selections to be made in conjunction with